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5. Compass
Pages 215-259

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From page 215...
... Thomson playfully applied scientific and mathematical principles to the matter of equipping his vessel. The question of fabric for the bedsheets, he explained to Mrs.
From page 216...
... By the spring of 1871, at any rate, Thomson was looking forward to sailing adventures as soon as the Glasgow teaching session ended. He urged Helmholtz to come to the British Association meeting at Edinburgh in early August then join him in a scientific party tO cruise the Hebrides and western isles on the Lalla Roomy He proposed to invite not only Maxwell and Tait (if he could be lured away from the golf course)
From page 217...
... Thomson wrote to his brotherin-law, the Rev. King, that Tyndall's suggestion was "especially inappropriate." Stokes said Tyndall was surely wrong: Atoms have no emotion or thought, so how could life made only of atoms acquire such things?
From page 218...
... 218 In the very beginnings of science, the parsons, who managed things then, Being handy with hammer and chisel, made gods in the likeness of men . He then mocked Tyndall's supposition that collections of atoms could do things that single atoms could not: For by laying their heads all together, the atoms, as councillors do, May combine to express an opinion to every one of them new.
From page 219...
... When a break from business in London presented itself, he took off for Lisbon and, sailing across the Bay of Biscay, began experiments on sounding devices. Traditionally, sailors threw a weighted line over the side to judge the depth of the water, but for an accurate sounding the ship had to come to a full halt.
From page 220...
... In the few quiet moments he could find, usually when he was alone on the Lalla Rooth, he struggled to compose his presidential address for the British Association's 1871 Edinburgh meeting, in which he resumed his attack on the geologists and biologists and proposed his cometary idea for the origin of life. Huxley and Tyndall declined Thomson's invitation to a postmeeting jaunt on the Lalla Root, as did Maxwell, who was preparing to take up his new appointment as Cavendish professor in Cambridge and who was in any case the exact antithesis of the jolly boating fellow.
From page 221...
... Assorted nephews and sisters-in-law joined and left at various places. They recrossed the Irish Sea and sailed about the west coast of Scotland until they reached the Blackburns' house at Rushven, on the Moidart peninsula.
From page 222...
... While sailing, he and Helmholtz had indulged in a sort of competition to see who could correctly explain the behavior of various waves and ripples they observed from the deck of the Lalla Root When Thomson had to leave the yacht for a while to attend to some problem ashore, he said jocularly, or perhaps not, "Now, mind, Helmholtz, you're not to work at waves while I'm away." A later commentator disparaged Thomson as someone who "had immense intellectual strength, but was deficient in intellectual taste." How could a man capable of founding thermodynamics and laying the groundwork for modern electromagnetic theory fritter
From page 223...
... Even though the tension on the wire was at most 50 pounds, Thomson realized, the effect was additive: Each turn of the reel added that much tension, so that if the whole length were wound in, over 100 tons of pressure would squeeze the reel.2 The crew had to stop and haul in something like a mile of thin wire by hand. Thomson devised a 2Try winding a length of dental floss around a finger.
From page 224...
... Again, Thomson showed his knack for putting together disparate elements, solving some practical difficulties, and coming up with a working system an empirical counterpart to his theoretical achievements in thermodynamics and electromagnetism. A series of patents in 1880, 1883, and 1885 stamped Thomson's name on the system, and although bureaucracy proved sluggish and reluctant, he succeeded in getting his device adopted by the Royal Navy and other navies.
From page 225...
... Peering through his eyeglass, Thomson interpreted the Morse code flapping: "Goodbye, goodbye, Sir William Thomson." Thomson was equally blithe about the occasion when he almost killed his friend Helmholtz, who was visiting his Glasgow laboratory. Showing off the sturdiness of a heavy rotating iron disc in some magnetic experiment, Thomson whacked it with a hammer, which sent it flying across the room.
From page 226...
... She traveled with him frequently and made her own social arrangements while he attended scientific or business meetings. Thomson's increasing wealth and reputation made him the center of a widening circle of notable acquaintances in business and politics as well as science, but Thomson himself had little time for purely social matters.
From page 227...
... G Knott on one occasion was with Thomson and Tait in Edinburgh and had agreed to write up Thomson's remarks to the Royal Society of Edinburgh for publication in Nature.
From page 228...
... This was important information for the Admiralty as the Royal Navy stationed itself across the globe, and the British Association had taken on tide prediction as an official project, with Thomson taking a lead role. It had been established that tides at any location could be analyzed into a series of harmonic components, each component having a certain period and a magnitude, from which tides could be predicted with good accuracy.
From page 229...
... In 1879 he composed a short paper for the Pro ceedir~gs of the Royal Society, with the title "Preliminary Note on a New Ticle-Preclictor." This came to Stokes, in his editorial capacity, who learned inclirectly that Thomson wished the title to be changed to "Preliminary Description of Sir William Thomson's Ticle Predictor Constructecl for the Indian Government." Stokes then related to Thomson how "utterly surprisecl" he was that this "very mild ancl unobjectionable" change caused Roberts to fly into a huff ancl refuse to have the paper published in its new form. In the end it was published with its original title, but then Roberts began to speak of the Roberts tide predictor ancl claim that the important part of the invention was his, acknowledging Thomson only for one or two useful hints.
From page 230...
... Finally, on Royal Navy expeditions to Australia in 1798 and 1801, Matthew Flinders systematically studied compass deviations and began to understand their origin. He noticed particularly that the departure of a compass needle from magnetic north changed sign when the ship crossed the equator that is, it
From page 231...
... Unaware, sailing the south seas, that France and England were at war, he was captured by the French in 1803 and remained a prisoner of war for several years. With ample opportunity for reflection, he came to the conclusion that compass deviation was related to the "dip" of the terrestrial magnetic field.
From page 232...
... . In 1835, on his own initiative, Captain Edward Johnson of the Royal Navy investigated compass deviation on the Garryower', a 130-foot-long iron paddle steamer with an enormous funnel 28 feet high.
From page 233...
... He speculated that as iron was heated and cooled and shaped and hammered, immersed all the while in the earth's magnetic field, it acquired permanent magnetism that was then built into the ship under construction. The British Admiralty finally lumbered into action, forming in 1837 a Compass Committee to address this "evil so pregnant with mischief"namely, the dismal performance of compasses on Her Majesty's warships.
From page 234...
... An iron ship, therefore, acts on a compass in two ways: There is a fixed, permanent, or hard magnetism and a variable, induced, or soft magnetism that depends (as Flinders had long ago found) on the ship's position relative to the earth's magnetic field in other words, on its latitude and heading.
From page 235...
... When Airy's compensation system proved inadequate, the Navy settled on a policy of mathematical correction but in a more sophisticated way than before. The soft iron deviation varied, as was now clear, with the ship's bearing, because of the dependence on angle between ship axis and magnetic field.
From page 236...
... A compass needle is a magnetized rod, which tries to align itself with the earth's magnetic field. Centuries ago, compass designers had learned to mount the needle on a support or card that floated in a bowl of water not a practical solution for a ship rocking around in a violent sea.
From page 237...
... During the mid-1840s hundreds of the new compasses were ordered and installed. The lurch into modernity signified by the Admiralty Standard Compass did not pull the rest of the Royal Navy along in its wake.
From page 238...
... Consequently, the Admiralty Standard Compass became part of entrenched naval practice when iron ships had not yet put in an appearance, so that compass errors were generally small and mathematical correction worked reasonably well. By the early 1 850s, when the Admiralty could no longer resist steam and iron, the Standard Compass system was inviolate, although difficulties in dealing with much greater compass errors were by then becoming apparent.
From page 239...
... A handful of elementary and unarguable physical principles dictated the dynamics and magnetic behavior of compasses. The interaction among the earth's magnetic field, the hard and soft magnetism of a
From page 240...
... As early as 1874 Thomson had written to Evans suggesting that a lighter compass card, properly suspended, would be more stable in heavy weather, and with guns firing, than the Admiralty Standard Compass card. Evans's cool reply, on top of the difficulty he had experienced in getting his sounding machine tested, caused Thomson to remark later that "innovation is very distasteful to sailors.
From page 241...
... Some naval historians have charged that Thomson gets too much credit for merely putting Airy's method into practice, but as well as adding the Flinders bar Thomson took pains to devise a system in which compensation would be both straightforward and trustworthy. Captain Evans of the Compass Department had complained with some justice that Airy's prescription was too loose to yield consistent results; there was insufficient guidance on the size and strength of magnets and correctors, how close they should be to the compass, and so on.
From page 242...
... The Thomson compass encountered problems, particularly a tendency to become unstable under rough conditions. Thomson refashioned the gimbals and the card suspension.
From page 243...
... Thomson heard "marvellously distinct" the words "to be or not to be" spoken through the device, along with a selection of items read from a local newspaper that were not so easy to make out. He brought back a pair of telephones from Philadelphia to show off at the British Association meeting in Glasgow later that year but had some difficulty with Bell's primitive microphone and couldn't get the apparatus to perform.
From page 244...
... Philadelphia, more cosmopolitan and confident, was not quite so overawed, but still the Inquirer ran a long account of the many famous men coming to town for the AAAS meeting, notable among them "Sir William Thomson, England's great mathematician and electrician." Thence Thomson went on to Baltimore, where in a story on events at Johns Hopkins the Sun announced that "the great event in the year's work will probably be the lectures by Sir William Thomson .
From page 245...
... Maxwell proposed certain general concepts electric and magnetic fields and showed mathematically how
From page 246...
... Some materials responded to a magnetic field by becoming magnetic themselves, in the same sense as the applied field. Others developed magnetism that opposed" the applied field.
From page 247...
... attended about half of the Baltimore lectures and remarked to his son years later: "What an extraordinary performance that was! I often recognized that the morning's lecture was founded on questions that had cropped up when we were talking at breakfast." This spontaneous disorderliness pleased Thomson's audience, Rayleigh thought, more than a set of carefully prepared talks would 7This afforded another opportunity for P
From page 248...
... , discoverer of the electron, remarked of William Thomson that "he has been known to lecture for an hour before reaching the subject of the lecture. It was only very rarely that he prepared either a speech or a lecture.
From page 249...
... A familiar medium, he concluded, could seem solid by the hour, but fluid by the month or year. This was relevant in understanding light, because the ether, to sustain the extremely rapid vibrations of light waves, must in some sense be rigid just as a chunk of hard metal, when struck, will ring at high pitch, whereas a more pliable block of wood would give a dull thud.
From page 250...
... The ether was like a wax or a jelly, he insisted; it was a matter of coming up with the appropriate characteristics which, Thomson admitted, he had not yet been able to do. In the printed version of his 20 Baltimore lectures, Thomson occupies more than 200 pages with seemingly endless calculations of the vibrations and oscillations of increasingly rococo arrangements of waxes and jellies, rods and springs, passive weights and gyrostats, in all combinations.
From page 251...
... "Platytatic" and "platythliptic," for example, became "sidelong normal" and "sidelong tangential." Whatever antique charm these words may once have possessed, the concepts they stand for have left no mark on modern physics. Thomson's aim, described but not achieved in his Baltimore lectures, was to find an ether, characterized by the correct set of values of the 21 coefficients, that would support oscillatory light waves with precisely their observed properties and relation to electric and magnetic stresses.
From page 252...
... In the end he abandoned mechanical pictures and, as one historian put it, presented his "Dynamical Theory of the Electromagnetic Field" in 1865 "stripped of the scaffolding by aid of which it had first been erected." Maxwell's is the modern strategy. Pictures and analogies of all and any kind are frequently useful in drawing up ideas for new theoretical constructs, but in the end those constructs stand or fall by their internal mathematical consistency and their empirical usefulness.
From page 253...
... They became great friends and allies. Two years later Fisher, still only 40, became captain of the Ir'~exilole, the largest ship in the Royal Navy.
From page 254...
... I will mention this to the British Association."' In fact, a man was electrocuted not long after in a similar accident. The potential was cut to 60 volts.
From page 255...
... Having become a champion for Thomson's compass, Fisher took no small pleasure in battling the Compass Department at every opportunity. "It was an immense cli~lculty getting the Aclmiralty tO adopt EThomson's]
From page 256...
... One day in 1885 he had been talking at the Admiralty with a captain who complained that his Thomson compass had been so poorly located, with respect to the iron structure of his ship, that he could hardly use it. By chance Mayes appeared just at that moment, and Fisher roundly declared to his colleague: "I can state from long experience that Capt Mayes may be relied upon to use every exertion to place Sir Wm Thomson's Compass in the worst possible position." "The result of this speech," Fisher later told Thomson, "was most gratifying I am convinced that the proper way to treat Capt Mayes is to deliberately and calmly insult him." In the meantime Thomson used the patent courts to fight offvarious competitors, with a determination that was often more thorough than admirable.
From page 257...
... The trick had been to design a chamber in which a compass card could float stably on water, under conditions of constant pressure, and with this and other improvements accomplished the liquid compass had far fewer of the dynamical problems associated with a dry card balanced on a pivot. The Royal Navy had recently commissioned a number of fast torpedo boats, and in these, when they moved at high speed, or in rough conditions, or with weaponry firing, both the old Admiralty Standard and the Thomson compass proved unstable and useless, while a simple liquid compass remained level.
From page 258...
... You can review the position of your compass as regards the Navy with pride and satisfaction." Years later, though, after he had retired, Creak confided to a friend: "When the Thomson compass was first introduced as Standard Compass on board I felt it my duty to try and make it a success. It was, however, in many respects the bete noire of my existence." It was not until after Creak had retired that his successor was able finally to introduce liquid compasses into the Royal Navy, Thomson having more or less retired from
From page 259...
... Scientific biographers of Thomson, if they have paid any attention at all to his compass innovations, have generally taken the matter to be a sorry saga of dim-witted naval administrators resisting marvelous innovations from a superlative scientific mind. Writers sympathetic to the Navy, on the other hand, portray Thomson as a man of undoubted talent and enthusiasm, with some genuine knowledge of the sea, who managed to parlay a handful of modest ideas in compass design into a commercial monopoly for his own manufacturing concern, using his reputation as a bludgeon in the law courts to beat down even small claims of originality from others, and persuading the Admiralty and the law to overlook both the deficiencies of his own design and the virtues of his competitors'.


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